This invention pertains to a kit of two integrated circuits (IC's) for a color television receiver with digital signal processing. The IC's contain a clock oscillator realized in the form of a phase-locked loop, for producing two phase clock signals. The phase comparator stage of the phase-locked loop is arranged in the first integrated circuit, and the voltage-controlled oscillator thereof is arranged in the second integrated circuit. The voltage control signals thereof are supplied via a maximum of two connecting lines from the first to the second integrated circuit. Such an IC kit is described on pages 1-3 and 1-4, 4-1 to 4-14 and 8-1 to 8-5 of the Intermetall book, "DIGIT 2000 VLSI-Digital-TV-System", March 1982. The pages beginning with the numeral 4 refer to the integrated circuit MAA 2200, and the pages beginning with the numeral 8 refer to the integrated circuit MEA 2600. On page 8-2 it is stated that the voltage-controlled oscillator as integrated into the integrated circuit MEA 2600 forms part of a phase-locked loop, with the other part thereof, i.e., the phase comparator, being integrated into the integrated circuit MAA 2200. The phase comparator stage supplies control signals to an external low-pass filter, i.e., one which is arranged outside the two integrated circuits, with this low-pass filter deriving the tuning voltages for the voltage-controlled oscillator from the control signals.
From an integration point of view, it is desirable to eliminate external discrete components. In addition thereto, the spatial separation of both the IC kit and the external low-pass filter presents a possible source of faults with respect to the DC and AC voltage behaviour of the control loop due to noise coupling owing to the voltage drop, as well as a capacitive or inductive coupling.